1. Field of the Invention
The present invention relates to abrasive blasting equipment and more particularly to a self-cleaning muffler which muffles the exhaust noise of an abrasive blast system and traps any particulate abrasive media which may exist in the system's exhaust.
2. Description of the Prior Art
Abrasive blast systems are pneumatic systems having, as a central component, an abrasive media holding tank which must be pressurized when the system is operated. When a blasting operation is terminated this holding tank (which can have one or more chambers) is rapidly depressurized through an exhaust line which on most conventional systems is remotely controlled by a pneumatically actuated exhaust valve. To trap abrasive media carried in the system's exhaust, an abrasive trap is often placed in line between the exhaust valve and the holding tank.
There are two well known problems associated with the depressurization of a conventional abrasive blast system. The first problem involves the environmental consideration of noise. When a conventional system depressurizes it does so with a loud blast or bang caused by high velocity air suddenly flowing out of the end of the exhaust line. The second problem is one of safety. As the system depressurizes particulate abrasive media is propelled at high velocity out of the exhaust line. The presence of an abrasive trap substantially mitigates this problem, however, it does not totally eliminate it. Although the outlet of the exhaust line is normally pointed downward to direct the high velocity exhaust into the ground, a person in the vicinity of the exhaust line nonetheless runs the risk of being struck by high velocity particulate.
The present invention overcomes the above problems of exhaust noise and exhausted high velocity particulate media by providing a self-cleaning muffler capable of being attached to the end of the abrasive blast system's exhaust line. The muffler according to the present invention both muffles the loud exhaust noise of the system and traps the high velocity particulate media carried by the exhaust, while permitting the trapped particulate to fall harmlessly to the ground once the abrasive holding tank has depressurized, that is, once the exhausting period of the system is completed.